The conventional control method for power supply or energy regulation, such as dimming control, generally adopts time cycle with an ON-OFF interval to regulate ON-OFF cycle (T1, T2) ratio to get different output energy (referring to FIG. 1). The excitation dynamical ratio (EDR) obtained by means of such an approach may be defined by equation-1 depicted below:
                              ≈                                                    E                1                            ⁡                              (                                  ON                  ⁢                                      -                                    ⁢                  Energy                  ⁢                                                                          ⁢                  cycle                                )                                                                    E                2                            ⁡                              (                                  OFF                  ⁢                                      -                                    ⁢                  Energy                  ⁢                                                                          ⁢                  cycle                                )                                                    ,                            (                  equation          ⁢                      -                    ⁢          1                )            
The conventional EDR is
            E      1                      E        ⁢                                  ⁢        2            ≈      0        ⇒  ∞
Based on equation-1, the conventional EDR is infinite. (Its meaning is similar to bending a steel wire to 90 degrees and straightening again. If the process is repeated many times, the steel wire will be ruptured. If the steel wire is bent only 10 degrees, it can be bent many more times than by bending 90 degrees before ruptured). The conventional energy control method set forth above has a great impact to the life span of the load. When the EDR is excessively large, the load has to function in two extreme conditions, and aging of the load is accelerated.
Another conventional method to control power supply (referring to FIGS. 2, 3 and 4) adopts EDR as follow:
                    E        A                    E        A              =    1    ,(Referring to FIG. 2)Total energy
      EA    ×    1    ⁢          (              T        TOTAL            )            T    TOTAL  (Maximum energy output)EDR:
                    1        2            ⁢      EA                      1        2            ⁢      EA        =  1(Half energy output), (Referring to FIG. 3)
            1      2        ⁢    Total    ⁢                  ⁢    energy    =                    1        2            ⁢      EA      ×      1              T      TOTAL      EDR:
                              1          10                ⁢        EA                              1          10                ⁢        EA              =    1    ,(Referring to FIG. 4)
            1      10        ⁢    Total    ⁢                  ⁢    energy    =                              1          10                ⁢        EA        ×        1                    T        TOTAL              ⁢          (                        1          10                ⁢        energy        ⁢                                  ⁢        output            )      
The method depicted above also has problems. When total regulation energy changes, the maximum wave amplitude of excitation energy also decreases. It could happen that the load cannot be actuated to function at one half of the amplitude energy (½EA) (such as the lamp cannot be ignited because of the voltage is too low, or some electromechanical elements cannot be activated because of the peak actuation energy is not adequate).